During the last year, we have constructed two plasmid vectors: one contains an Emerald marker driven by Zscan4 promoter; and the other contains a Strawberry marker driven by Trim43 promoter. We have carried out the pronuclear injection of these two plasmids and obtained pups. We are currently testing the germline transmission of the transgenes and whether two fluorescent proteins can be expressed as we designed. We will then establish homozygous transgenic mouse lines, in which both Emerald (Zscan4) and Strawberry (Trim43) are sequentially expressed during preimplantation development.